PHP (PHP: Hypertext Preprocessor) is a versatile, general-purpose scripting language. While it is most famous for server-side web development where scripts are processed by a web server to generate dynamic content, it also includes a powerful Command Line Interface (CLI). The PHP CLI allows scripts to be executed directly from a terminal or command prompt, making it suitable for a wide range of tasks outside of a web context, such as automation, data processing, and system administration scripts. This dual capability is a key feature of the language.

A. PHP is a cross-platform language, officially supported on various operating systems, including Linux, Windows, macOS, and others, not just Linux.

B. The PHP Command Line Interface (CLI) SAPI (Server Application Programming Interface) is specifically designed for running scripts outside of a web server.

C. PHP's primary and most widespread use is for server-side scripting in web applications, where it is processed by a web server.

1. The PHP Group, PHP Manual, "What is PHP?". "PHP is a popular general-purpose scripting language that is especially suited to web development. [...] But PHP can do much more. There are three main areas where PHP scripts are used. - Server-side scripting. [...] - Command line scripting. [...] - Writing desktop applications." This section explicitly states the main uses, including both server-side (web) and command-line scripting.

Source: https://www.php.net/manual/en/intro-whatis.php

2. The PHP Group, PHP Manual, "Using PHP from the command line". "PHP is not only for creating web pages. Since PHP 4.3.0, PHP has a new SAPI type named CLI, which stands for Command Line Interface. As the name implies, this SAPI type main focus is on developing shell (or desktop) applications with PHP." This document details the existence and purpose of the CLI, confirming its use beyond web applications.

Source: https://www.php.net/manual/en/features.commandline.php